Non-carbohydrate foaming compositions and methods of making the same

ABSTRACT

A foaming composition includes a powdered carbohydrate-free soluble composition which includes protein particles having a plurality of internal voids containing entrapped pressurized gas. In one form, the foaming composition is produced by subjecting the particles to an external gas pressure exceeding atmospheric pressure prior to or while heating the particles to a temperature of at least the glass transition temperature and then cooling the particles to a temperature below the glass transition temperature prior to or while releasing the external pressure in a manner effective to trap the pressurized gas within the internal voids.

FIELD OF THE INVENTION

The present invention relates to soluble foaming compositions, and inparticular, carbohydrate-free foaming protein compositions which containpressurized gas.

BACKGROUND OF THE INVENTION

Some conventionally prepared food items include froth or foam. Forexample, cappuccino, milk shakes, and some soups may have froth or foam.While conventionally prepared food items may be considered preferable bysome consumers, other consumers are increasingly demanding theconvenience of consumer prepared instant food alternatives. In order toaccommodate consumer preferences, manufactures have developed instantfood products which give consumers the food products they demand from aconvenient instant food product by developing instant food items whichhave the same or similar characteristics as conventionally prepared fooditems. One challenge for manufacturers is how to produce a food producthaving froth or foam from an instant food item.

One prior solution used to manufacture an instant food product which hasfroth or foam is through the use of powdered foaming compositions whichproduce foam upon reconstitution in a liquid. Foaming powdercompositions have been used to impart froth or foamed texture to a widevariety of foods and beverages. For example, foaming compositions havebeen used to impart froth or foamed texture to instant cappuccino andother coffee mixes, instant refreshing beverage mixes, instant soupmixes, instant milkshake mixes, instant dessert toppings, instantsauces, hot or cold cereals, and the like, when combined with water,milk, or other suitable liquid.

Some examples of gas-injected foaming creamers which can be used toimpart foam or froth are disclosed in U.S. Pat. No. 4,438,147 and in EP0 458 310. More recently, U.S. Pat. No. 6,129,943 discloses a foamingcreamer produced by combining a gasified carbohydrate with protein andlipid. Using this technology, it was possible to eliminate gas injectionof the liquid creamer composition prior to spray drying.

EP 0 813 815 B1 discloses a foaming creamer composition which is eithera gas-injected foaming creamer or a creamer containing chemicalcarbonation ingredients which contains in excess of 20% protein byweight. The powder described has as essential ingredients, protein,lipid and filler material, the filler especially being a water-solublecarbohydrate. The high content of protein is needed to obtain a whippedcream-like, tight foam having spoonability.

One prior foaming composition is provided by U.S. Pat. No. 6,713,113which discloses a powdered soluble foaming ingredient comprised of amatrix containing carbohydrate, protein, and entrapped pressurized gas.However, powdered ingredients containing both carbohydrate and proteinare susceptible to nonoxidative browning reactions that can adverselyaffect the appearance, flavor, and shelf life of packaged food products.These complex chemical reactions occur between proteins andcarbohydrates, especially reducing sugars, to form polymeric pigmentsthat can severely discolor and diminish the flavor quality of foodproducts. It has been discovered that highly effective foamingcompositions containing entrapped pressurized gas can be manufacturedwithout the need to use both carbohydrate and protein ingredients.Browning can occur very rapidly at high temperatures commonly used infood processing and susceptibility to browning can limit the range ofheating conditions used to produce foaming compositions of the typedisclosed in the aforementioned prior art.

A possible solution could be the use of a substantially protein-onlycomposition, as described in WO-A-2004/019699. However, the use ofprotein itself also poses some problems. More importantly, none of thedisclosed examples in the published patent application are devoid ofcarbohydrate.

U.S. Pat. No. 6,168,819 describes a particulate creamer comprisingprotein, lipid, and carrier, in which more than 50% by weight of theprotein is partially denatured whey protein, the partially denaturedwhey protein being from 40 to 90% denatured. The total protein contentof the creamer is between 3 and 30% by weight, preferably between 10 and15% by weight. The creamer is particularly suitable for foaming creamercompositions. The foaming creamer composition, when added to a brewedhot coffee beverage, produces a large amount of creamy semi-solid foam.

U.S. Pat. No. 6,174,557 describes an instant particulate dry mixcomposition that produces a cappuccino beverage having surface foam witha marbled appearance upon reconstitution in water. The dry mixcomposition is made by deaerating and subsequently freeze drying acoffee extract to produce granules having an outer surface layer whichis rapidly soluble and a larger inner core layer which is slowlysoluble. The product has a density of at least 0.3 g/cc.

U.S. patent Publication No. 2003/0026836 discloses a method for formingtablets or powders of carbohydrate-based pharmaceuticals or foods whichincludes subjecting tablets or powders which comprise a beverage basesuch as soluble coffee, foamed powder, sugar and creamer to pressure andtemperature to produce a tablet or powder with increased solubility ordispersability on contact with water. In addition, a method is disclosedwhich promotes the dissolution or dispersion of a tablet or non-foamingpowder by subjecting the tablet or powder to pressurized gas so that gasis entrapped therein to promote dissolution or dispersion of the tabletor powder on contact with water. It is notable that all examplesprovided therein of soluble compositions are powder or tabletcompositions containing carbohydrate. Improved dissolution of tabletscontaining entrapped gas is demonstrated in working examples therein.However, improved dissolution or dispersability of powders, foaming ornon-foaming, containing entrapped gas is not demonstrated in any workingexample therein. More importantly, this reference does not disclose asoluble composition containing pressurized gas nor a method formanufacturing a soluble composition containing pressurized gas.

A disadvantage of prior foaming additives, as well as of many priorproducts, is that both proteins and carbohydrates are present. Moreimportantly, even art directed to forming substantially protein-onlycompositions, such as WO-A-2004/019699, fail to disclose a workingexample devoid of carbohydrate. In fact, none of the relevant prior artdiscloses a working example or any reduction to practice of a foamingprotein composition devoid of carbohydrate. The foaming composition ofWO-A-2004/019699 that forms the basis of all working examples disclosedtherein contains carbohydrate glycerol at a level of 5% by weight. Infact, none of the relevant prior art discloses a working example or anyreduction to practice of a foaming carbohydrate composition devoid ofprotein.

Proteins can react with carbohydrates, especially when heated. Most ofthe time these (Maillard) reactions lead to undesired coloring and/orformation of off-flavor. This type of reaction generally occurs duringprocessing or manufacturing, when the product is kept at highertemperatures for some time and often if it is kept at highertemperatures for prolonged times. In most of the preparation processesfor the products described in the documents discussed herein-above, andparticularly in the preparation processes described in U.S. Pat. No.6,168,819, a prolonged time at elevated temperatures is used to gasifythe powders.

Further, since prior foaming coffee additives include both acarbohydrate component and a protein component, people on restrictivediets wishing to avoid one of the two components will not be able toconsume beverages including any of the prior additives.

Although foaming coffee additives are available, there is still a needfor a powdered carbohydrate-free soluble foaming composition which, uponreconstitution, exhibits a foam characteristic desired by truecappuccino beverage connoisseurs. For example, prior resultingcappuccino beverages containing foaming additives lack sufficient foam,the foam dissipates too quickly or there is a combination of both. Inaddition, none of the relevant prior art discloses a working example orany reduction to practice of a foaming protein composition devoid ofcarbohydrate.

SUMMARY OF THE INVENTION

The present invention relates to a non-carbohydrate, i.e.,carbohydrate-free foaming composition which provides excellentresistance to browning and can provide additional advantages. Forexample, the carbohydrate-free foaming composition can supportlow-carbohydrate diets. In addition, the improved foaming compositioncan be used in a wide variety of hot and cold beverage mixes and otherinstant food products to provide froth or foamed texture.

The present invention, in one form thereof, concerns a foamingcomposition which comprises a powered carbohydrate-free solublecomposition comprising protein particles having a plurality of internalvoids containing entrapped pressurized gas. In further alternate forms,the soluble composition releases at least about 2 cc or at least about 5cc of gas per gram of the composition when dissolved in a liquid, andthe soluble composition is selected from the group comprising a milkprotein, soy protein, egg protein, gelatin, collagen, whey protein, andmixtures thereof. In yet a further form, the composition may include abuffering agent such as a salt of an organic or inorganic acid.

The present invention in another form thereof concerns a foamingcomposition which comprises carbohydrate-free soluble foaming particlescomprising a protein and having a plurality of internal voids containingentrapped pressurized gas. The foaming composition is formed bysubjecting the particles to an external gas pressure exceedingatmospheric pressure prior to or while heating the particles to atemperature of at least the glass transition temperature (T_(g)) andthen cooling the particles to a temperature below the T_(g) prior to orwhile releasing the external gas pressure in a manner effective to trapthe pressurized gas within the internal voids.

The present invention in another form thereof concerns a solubleconsumable food product comprising a carbohydrate-free soluble foamingcomposition which comprises protein particles having a plurality ofinternal voids containing entrapped pressurized gas. In various furtherforms, the soluble food product may include a beverage mix such ascoffee, cocoa, or tea, such as instant coffee, cocoa or tea, or thesoluble consumable product may include an instant food product such asan instant dessert product, instant cheese product, instant cerealproduct, instant soup product, and an instant topping product.

The present invention in yet another form thereof concerns a method formanufacturing a foaming composition in which the method includes heatingcarbohydrate-free soluble foaming particles which includes a proteinwhich has internal voids. An external pressure exceeding atmosphericpressure is applied to the carbohydrate-free soluble foaming particles.The carbohydrate-free soluble foaming particles are cooled and theexternal gas pressure is released thereby resulting in pressurized gasremaining in the internal voids. In further alternate forms, theexternal pressure is applied prior to heating the particles or theexternal pressure is applied while heating the particles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Ingredients that can be used to formulate carbohydrate-free powdersinclude proteins, lipids, and other carbohydrate-free substances.Proteins are preferred and include, but are not limited to, milkproteins, soy proteins, egg proteins, gelatin, collagen, wheat proteins,and hydrolyzed proteins. Suitable hydrolyzed proteins include hydrolyzedgelatin, hydrolyzed collagen, hydrolyzed casein, hydrolyzed wheyprotein, hydrolyzed milk protein, hydrolyzed soy protein, hydrolyzed eggprotein, hydrolyzed wheat protein, and amino acids. The protein or themixture of proteins is selected such that the foaming compositionstructure is sufficiently strong to retain the gas enclosed underpressure.

Hydrolyzed gelatin is preferred because of its superior chemical andphysical properties. It not only provides excellent gas entrapmentcharacteristics, foamability, and flavor, but also is completely devoidof carbohydrate, and further, unlike other protein sources listed above,is non-allergenic. As an alternative to hydrolyzed gelatin, gelatin canbe used. Accordingly, the use of hydrolyzed gelatin or gelatin can beadvantageous to manufacturing foaming compositions containing entrappedpressurized gas.

Food ingredients that are both protein-free and carbohydrate-free can beused in combination with proteins and may include, but are not limitedto, organic and inorganic salts, surfactants, emulsifiers,phytochemicals, nutritional additives, flow agents, artificialsweeteners, preservatives, colorants, and some flavors. Lipids include,but are not limited to, fats, oils, hydrogenated oils, interesterifiedoils, phospholipids, and fatty acids derived from vegetable, dairy, oranimal sources, and fractions or mixture thereof. The lipid may also beselected from waxes, sterols, stanols, terpenes, and fractions ormixture thereof. Examples of possible emulsifiers include an emulsifierselected from the group consisting of Tween 20 (polyoxyethylenesorbitanmonolaureate), SSL (sodium stearoyl-2-lactylate) or sucroseester.

The powdered soluble carbohydrate-free foaming ingredients of thisinvention can be produced by any method effective to provide aparticulate structure having a plurality of internal voids capable ofentrapping pressurized gas. Conventional gas-injected spray drying ofaqueous solutions is the preferred method to manufacture these powderedsoluble foaming compositions, but gas-injected extrusion of powder meltsis also a suitable method. Spray drying without gas injection typicallyproduces particles having relatively small internal void volumes, butthis less preferred method can also be used to manufacturecarbohydrate-free foaming compositions having suitable internal voidvolumes. Nitrogen gas is preferred, but any other food-grade gas can beused for gas injection, including air, carbon dioxide, nitrous oxide, ormixture thereof.

The term “entrapped pressurized gas” means that gas having a pressuregreater than atmospheric pressure is present in the foaming compositionstructure and is not able to leave this structure, without opening thepowder structure. Preferably, the majority of the pressurized gaspresent in the foaming composition structure is contained physicallywithin internal voids of the powder structure. Gases that can suitablybe used according to the present invention can be selected fromnitrogen, carbon dioxide, nitrous oxide, air, or mixture thereof.Nitrogen is preferred, but any other food-grade gas can be used toentrap pressurized gas in the powder structure.

The term “structure”, “particulate structure”, “particle structure”, or“powder structure” means the structure contains a large number of sealedinternal voids which are closed to the atmosphere. These voids arecapable of holding a large volume of entrapped pressurized gas that isreleased as bubbles upon dissolution of the structure in liquid toproduce foam.

The term powdered soluble foaming composition”, “powdered foamingcomposition”, or “foaming composition” means any powder that is solublein, or disintegrates in a liquid, and especially in an aqueous liquid,and that upon contact with such liquid forms a foam or froth.

The term “carbohydrate-free” or “non-carbohydrate” means to conveyintentional and deliberate avoidance of substances containing anysignificant amount of carbohydrate, to the greatest practical extent, inthe formulation of foaming compositions. Accordingly, thecarbohydrate-free foaming compositions of this invention are virtuallyfree or devoid of carbohydrate and contain substantially less than 1%,and typically less than about 0.5%, carbohydrate. Preferredcarbohydrate-free compositions of this invention are devoid ofcarbohydrate. The hydrolyzed gelatin foaming compositions disclosed inthe examples herein are devoid of carbohydrate.

Weight percentages are based on the weight of the final powdered foamingcomposition, unless otherwise indicated.

The term “emulsifier” means any surface-active compound that has oil orgas emulsifying properties which is compatible with the end use of thepowder of the invention, has emulsifying properties and is not aprotein.

The term “essentially 100% protein” used in reference to thenon-carbohydrate protein foaming composition means that the compositionis essentially all protein with only trace amounts of non-proteinconstituents being less than 1% on a dry basis. The foaming compositionmay have a moisture content between 0-15%, typically 1-10%, moretypically 2-5% and water activity between 0-0.5, typically 0.05-0.4, andmore typically 0.1-0.3.

Advantages of the foaming composition according to the invention arethat, upon contact with a suitable liquid, an amount of foam is formedwhich provides desirable color, mouthfeel, density, texture, andstability when used to formulate instant cappuccino mixes or otherproducts. Since it contains no carbohydrate, adverse side effectsassociated with protein/carbohydrate mixtures, such as Maillardreaction, and/or reactions between proteins and other substituents, donot occur or at least are reduced.

It is optional to formulate the foaming ingredient compositions of thisinvention using one or more surfactants to improve bubble formation andcreation of internal voids during spray drying or extrusion. Use ofsuitable surfactants at appropriate levels can be used to influence therelative size, number, and volume of internal voids available forentrapping gas. Because most food proteins are naturally surface-active,suitable carbohydrate-free compositions containing protein can bemanufactured with adequate internal void volumes without the need forsurfactants. Surfactants include food-approved emulsifying agents suchas polysorbates, sucrose esters, stearoyl lactylates,mono/di-glycerides, diacetyl tartaric esters of mono/di-glycerides, andphospholipids.

Formulation of protein-based carbohydrate-free foaming compositions ofthis invention using one or more buffering agents can be used tofacilitate spray drying and reconstitution in liquid. Preferredbuffering agents used in this invention are salts of organic orinorganic acids. Buffering agents increase the buffering capacity ofproteins in the foaming composition to improve resistance to aggregationor denaturation in certain product applications such as acidicbeverages. The most preferred buffering agents are sodium and potassiumsalts of organic acids. Suitable buffering agents include, but are notlimited to, sodium, potassium, calcium, and magnesium salts of citric,malic, fumaric, and phosphoric acid.

Powders which are used for entrapping pressurized gas to manufacture thefoaming compositions of this invention have a bulk and tap density inthe range of 0.1-0.7 g/cc, typically 0.2-0.6 g/cc, a skeletal density inthe range of 0.3-1.6 g/cc, typically 0.4-1.5 g/cc, a true density of1.2-1.6 g/cc, and an internal void volume in the range of 5-80%,typically 10-75%, before subjecting to external gas pressure. Powderswith relatively large internal void volumes are generally preferredbecause of their greater capacity to entrap gas. Internal void volume issuitably at least about 10%, preferably at least about 30%, and morepreferably at least about 50%. The powders have a glass transitiontemperature between 30-150° C., typically 40-125° C., and more typically50-100° C. The powders have a moisture content between 0-15%, typically1-10%, more typically 2-5% and water activity between 0-0.5, typically0.05-0.4, and more typically 0.1-0.3.

Bulk density (g/cc) is determined by measuring the volume (cc) that agiven weight (g) of material occupies when poured through a funnel intoa graduated cylinder. Tap density (g/cc) is determined by pouring thepowder into a graduated cylinder, vibrating the cylinder until thepowder settles to its lowest volume, recording the volume, weighing thepowder, and dividing weight by volume. Skeletal density (g/cc) isdetermined by measuring the volume of a weighed amount of powder using ahelium pycnometer (Micromeritics AccuPyc 1330) and dividing weight byvolume. Skeletal density is a measure of density that includes thevolume of any voids present in the particles that are sealed to theatmosphere and excludes the interstitial volume between particles andthe volume of any voids present in the particles that are open to theatmosphere. The volume of sealed voids, referred to herein as internalvoids, is derived from also measuring the skeletal density of the powderafter grinding with mortar and pestle to remove or open all internalvoids to the atmosphere. This type of skeletal density, referred toherein as true density (g/cc), is the actual density of only the solidmatter comprising the powder. Internal void volume (%), the volumepercent of sealed internal voids contained in the particles comprisingthe powder, is determined by subtracting the reciprocal true density(cc/g) from the reciprocal skeletal density (cc/g) and then multiplyingthe difference by skeletal density (g/cc) and 100%.

The glass transition temperature marks a secondary phase changecharacterized by transformation of the powder composition from a rigidglassy state to a softened rubbery state. In general, gas solubilitiesand diffusion rates are higher in materials at or above the glasstransition temperature. The glass transition temperature is dependent onchemical composition and moisture level and, in general, lower averagemolecular weight and/or higher moisture will lower glass transitiontemperature. The glass transition temperature can intentionally beraised or lowered by simply decreasing or increasing, respectively, themoisture content of the powder using any suitable method known to oneskilled in the art. Glass transition temperature can be measured usingestablished Differential Scanning Calorimetry or Thermal MechanicalAnalysis techniques.

Novel foaming compositions of this invention that contain entrappedpressurized gas can be manufactured by heating the carbohydrate-freepowder having appropriate particle structure under pressure in anysuitable pressure vessel and cooling the powder either by rapid releaseof pressure or by cooling the vessel prior to depressurization. Thepreferred method is to seal the powder in the pressure vessel andpressurize with compressed gas, then heat the pressure vessel either byplacing in a preheated oven or bath or by circulation of electriccurrent or hot fluid through an internal coil or external jacket toincrease the temperature of the powder to above the glass transitiontemperature for a period of time effective to fill internal voids in theparticles with pressurized gas, then cool the still pressurized vesselcontaining the powder to about room temperature either by placing in abath or by circulation of cold fluid, then release the pressure and openthe vessel to recover the foaming composition. The foaming compositioncan be produced in batches or continuously using any suitable means.Novel foaming compositions of this invention that contain atmosphericpressure gas can be produced in the same manner with the exception thatheating is conducted below the glass transition temperature of thepowder.

In general, powders are heated at a temperature in the range of 20-200°C., preferably 40-175° C., and more preferably 60-150° C. for 1-300minutes, preferably 5-200 minutes, and more preferably 10-150 minutes.The pressure inside the pressure vessel is in the range of 20-3000 psi,preferably 100-2000 psi, and more preferably 300-1500 psi. Use ofnitrogen gas is preferred, but any other food-grade gas can be used topressurize the vessel, including air, carbon dioxide, nitrous oxide, ormixture thereof. Powder gas content and foaming capacity generallyincrease with processing pressure. Heating can cause the initialpressure delivered to the pressure vessel to increase considerably. Themaximum pressure reached inside the pressure vessel during heating canbe approximated by multiplying the initial pressure by the ratio ofheating temperature to initial temperature using Kelvin units oftemperature. For example, pressurizing the vessel to 1000 psi at 25° C.(298 K) and then heating to 120° C. (393 K) should increase the pressurein the pressure vessel to approximately 1300 psi.

At temperatures at or above the T_(g), particle gas content and foamingcapacity increase with processing time until a maximum is reached. Therate of gasification generally increases with pressure and temperatureand relatively high pressures and/or high temperatures can be used toshorten processing time. However, increasing temperature to greatlybeyond what is required for effective processing can make the powdersusceptible to collapse. Particle size distribution of the powders istypically not meaningfully altered when gasification is conducted undermore preferred conditions. However, significant particle agglomerationor caking can occur when gasification is conducted under less preferredconditions such as excessively high temperature and/or long processingtime. It is believed that gas dissolved in the softened gas-permeablesolid matter during heating diffuses into internal voids until pressureequilibrium is reached or until the powder is cooled to below the T_(g).Therefore, it is to be expected that the cooled particles should retainboth pressurized gas entrapped in internal voids and gas dissolved inthe solid matter.

When powders are pressurized at a temperature at or above the T_(g), itis common for some of the particles to explode with a loud crackingsound during a brief time after depressurization due to bursting oflocalized regions of the particle structure that are too weak to retainthe pressurized gas. In contrast, when powders are pressurized below theT_(g) and depressurized, it is less common for particles to explode andany explosions occur with less sound and force. However, it is commonfor these particles to produce a faint popping sound during a brief timeafter depressurization. Powder appearance and bulk density are typicallynot significantly altered by pressurizing below the T_(g), but skeletaldensity and internal void volume are typically significantly altered.

The foaming compositions retain pressurized gas with good stability whenstored below the T_(g) with adequate protection against moistureintrusion. Foaming compositions stored in a closed container at roomtemperature generally perform well many months later. Powderspressurized below the T_(g) do not retain pressurized gas for a longperiod of time. However, it has been surprisingly discovered thatspray-dried powders that are pressurized below the T_(g) typicallyproduce significantly more froth than the unpressurized powders evenafter the pressurized gas is lost. It is believed that this beneficialincrease in foaming capacity is caused by infiltration of atmosphericpressure gas into previously vacuous internal voids formed byevaporation of water from the particles during drying. It has been foundthat this novel method to increase the foaming capacity of spray-driedfoaming compositions can be conducted at room temperature with excellentresults.

Foaming compositions manufactured according to the embodiments of thisinvention have a bulk density and a tap density in the range of 0.1-0.7g/cc, typically 0.2-0.6 g/cc, a skeletal density in the range of 0.3-1.6g/cc, typically 0.5-1.5 g/cc, and more typically 0.7-1.4 g/cc, a truedensity in the range of 1.2-1.6 g/cc, an internal void volume in therange of 2-80%, typically 10-70%, and more typically 20-60%, and containpressurized gas in the range of 20-3000 psi, typically 100-2000 psi, andmore typically 300-1500 psi. As a point of reference, atmosphericpressure is about 15 psi at sea level. Pressure treatment at anytemperature typically increases skeletal density and decreases internalvoid volume. Bulk density is typically not significantly altered bypressure treatment below the T_(g), but is typically increased bypressure treatment above the T_(g). Changes in bulk density, skeletaldensity, and internal void volume are collectively determined by powdercomposition and processing conditions including treatment time,temperature, and pressure. The powdered foaming compositions containingentrapped pressurized gas generally have particle size between about 1to 5000 microns, typically between about 5 to 2000 microns, and moretypically between about 10 to 1000 microns.

The preferred use for these novel foaming compositions is in solublebeverage mixes, particularly instant coffee and cappuccino mixes.However, they can be used in any instant food product that is rehydratedwith liquid. Although these foaming compositions typically dissolve wellin cold liquids to produce froth, dissolution and foaming capacity aregenerally improved by reconstitution in hot liquids. Applicationsinclude instant beverages, desserts, cheese powders, cereals, soups,topping powders, and other products.

The following examples are included to provide better understanding ofthe present invention but in no way limit the scope or breadth thereof.

EXAMPLE 1

A commercial carbohydrate-free (0.0% carbohydrate) hydrolyzed gelatinpowder, produced by spray drying an aqueous solution without gasinjection, was obtained. The 99.2% dry-basis protein powder had lightyellow color, a bulk density of 0.45 g/cc, a tap density of 0.54 g/cc, askeletal density of 1.15 g/cc, an internal void volume of 18%, a truedensity of 1.41 g/cc, a T_(g) of 70° C., and moisture content of about6%. The powder was added to an instant cappuccino mix, using a weightratio of about one part powder to one part soluble coffee to two partssugar to three parts foaming creamer. Reconstitution of about 13 g ofthe cappuccino mix in a 250 ml beaker having 65 mm internal diameterusing 130 ml of 88° C. produced an amount of froth that completelycovered the surface of the beverage to a height of about 14 mm.

6 g of the carbohydrate-free powder was pressurized at 25° C. withnitrogen gas at 1000 psi for 5 minutes in a stainless steel pressurevessel (75 cc capacity gas-sampling. cylinder; manufactured by WhiteyCorporation; used in all examples herein) and then depressurized.Replacing the untreated powder with an equal weight of treated powder inthe cappuccino mix revealed that treatment increased the foamingcapacity of the powder by about 150%. Knowledge of the reconstitutedbeverage mix froth density and incremental froth volume contributed bythe treated and untreated powders was used to estimate the amount(corrected to room temperature and pressure) of gas released by eachpowder. It was estimated that the untreated powder released about 2 ccgas per gram of powder while the treated powder released about 5.5 ccgas per gram of powder. The powder produced a faint popping sound for ashort time after depressurization. Bulk density of the treated powderwas not altered, but skeletal density increased to 1.24 g/cc andinternal void volume decreased to 12%, indicating the force ofpressurization and/or depressurization opened a portion of previouslyvacuous internal voids, formed during particle dehydration, to theatmosphere to increase foaming capacity. This hypothesis is supported bythe fact that even after one week, the treated powder retained increasedfoaming capacity.

Another 6 g sample of the carbohydrate-free powder was pressurized withnitrogen gas at 1000 psi, heated in a 120° C. oven for 15 minutes, andthen cooled to about room temperature before depressurizing. Thetreatment trapped pressurized gas in the powder and many particlesexploded for a short time after depressurization. The treated powder hadlight yellow color, a tap density of 0.54 g/cc, a skeletal density of1.28 g/cc, and an internal void volume of 9%. Replacing the untreatedpowder with an equal weight of treated powder in the cappuccino mixrevealed that treatment increased the foaming capacity of the powder byover 2-fold, increasing the amount of gas released from about 2 cc gasper gram of powder to about 5.5 cc gas per gram of powder.

Another 6 g sample of the carbohydrate-free powder was pressurized withnitrogen gas at 1000 psi, heated in a 120° C. oven for 30 minutes, andthen cooled to about room temperature before depressurizing. Thetreatment trapped pressurized gas in the powder and many particlesexploded for a short time after depressurization. The treated powder hadlight yellow color, a tap density of 0.54 g/cc, a skeletal density of1.33 g/cc, and an internal void volume of 6%. Replacing the untreatedpowder with an equal weight of treated powder in the cappuccino mixrevealed that treatment increased the foaming capacity of the powder byover 4-fold, increasing the amount of gas released from about 2 cc gasper gram of powder to about 9 cc gas per gram of powder.

Another 6 g sample of the carbohydrate-free powder was pressurized withnitrogen gas at 1000 psi, heated in a 120° C. oven for 60 minutes, andthen cooled to about room temperature before depressurizing. Thetreatment trapped pressurized gas in the powder and a comparably largerproportion of particles exploded for a short time afterdepressurization. The treated powder had light yellow color, a tapdensity of 0.52 g/cc, a skeletal density of 1.28 g/cc, and an internalvoid volume of 9%. Replacing the untreated powder with an equal weightof treated powder in the cappuccino mix revealed that treatmentincreased the foaming capacity of the powder by 6-fold, increasing theamount of gas released from about 2 cc gas per gram of powder to about12.5 cc gas per gram of powder. All cappuccino beverages had excellentflavor.

EXAMPLE 2

A commercial carbohydrate-free (about 0.1% residual lactose) hydrolyzedsodium caseinate powder, produced by spray drying an aqueous solutionwithout gas injection, was obtained. The 94.5% dry-basis protein powderhad light yellow color, clean milky odor and flavor, a bulk density of0.27 g/cc, a tap density of 0.45 g/cc, a skeletal density of 1.28 g/cc,an internal void volume of 7%, a true density of 1.37 g/cc, a T_(g) of69° C., and moisture content of about 4%. Use of the powder in aninstant sweetened coffee mix, using a weight ratio of about three partspowder to one part soluble coffee to two parts sugar, produced an amountof froth that completely covered the surface of the beverage to a heightof about 5 mm when about 11 g of the mix was reconstituted in a 250 mlbeaker having 65 mm internal diameter using 130 ml of 88° C. water.

6 g of the carbohydrate-free powder was pressurized at 25° C. withnitrogen gas at 1000 psi for 5 minutes in a pressure vessel and thendepressurized. Replacing the untreated powder with an equal weight oftreated powder in the sweetened coffee mix revealed that treatmentincreased the foaming capacity of the powder by about 65%. Knowledge ofthe reconstituted beverage mix froth density and incremental frothvolume contributed by the treated and untreated powders was used toestimate the amount (corrected to room temperature and pressure) of gasreleased by each powder. It was estimated that the untreated powderreleased about 1.25 cc gas per gram of powder while the treated powderreleased about 2 cc gas per gram of powder. The powder produced a faintpopping sound for a short time after depressurization. Bulk density andskeletal density of the treated powder were not measurably altered, butthe increased foaming capacity indicated the force of pressurizationand/or depressurization opened a portion of previously vacuous internalvoids formed during particle dehydration.

Another 6 g sample of the carbohydrate-free powder was pressurized withnitrogen gas at 1000 psi, heated in a 120° C. oven for 15 minutes, andthen cooled to about room temperature before depressurizing. Thetreatment trapped pressurized gas in the powder and produced a faintpopping sound for a short time after depressurization without visibleparticle explosions. The treated powder had light yellow color, a tapdensity of 0.43 g/cc, a skeletal density of 1.28 g/cc, and an internalvoid volume of 7%. Replacing the untreated powder with an equal weightof treated powder in the sweetened coffee mix revealed that treatmentincreased the foaming capacity of the powder by over 3-fold, increasingthe amount of gas released from about 1.25 cc gas per gram of powder toabout 4.5 cc gas per gram of powder.

Another 6 g sample of the carbohydrate-free powder was pressurized withnitrogen gas at 1000 psi, heated in a 120° C. oven for 30 minutes, andthen cooled to about room temperature before depressurizing. Thetreatment trapped pressurized gas in the powder and produced a faintpopping sound for a short time after depressurization without visibleparticle explosions. The treated powder had light yellow color, a tapdensity of 0.44 g/cc, a skeletal density of 1.30 g/cc, and an internalvoid volume of 5%. Replacing the untreated powder with an equal weightof treated powder in the sweetened coffee mix revealed that treatmentincreased the foaming capacity of the powder by over 8-fold, increasingthe amount of gas released from about 1.25 cc gas per gram of powder toabout 10.5 cc gas per gram of powder.

Another 6 g sample of the carbohydrate-free powder was pressurized withnitrogen gas at 1000 psi, heated in a 120° C. oven for 60 minutes, andthen cooled to about room temperature before depressurizing. Thetreatment trapped pressurized gas in the powder and produced a faintpopping sound for a short time after depressurization without visibleparticle explosions. The treated powder had light yellow color, a tapdensity of 0.43 g/cc, a skeletal density of 1.32 g/cc, and an internalvoid volume of 4%. Replacing the untreated powder with an equal weightof treated powder in the sweetened coffee mix revealed that treatmentincreased the foaming capacity of the powder by 10-fold, increasing theamount of gas released from about 1.25 cc gas per gram of powder toabout 12.5 cc gas per gram of powder. All sweetened coffee beverages hadexcellent clean milky flavor and odor.

EXAMPLE 3

An additional 5 g sample of the untreated carbohydrate-free powder ofExample 1 was mixed with 28 g of Swiss Miss® Hot Cocoa Mix. The mix wasreconstituted with 180 ml of 90° C. in a 250 ml beaker having 65 mminternal diameter to produce a hot cocoa beverage at a height of about60 mm that was completely covered by froth at a height of about 7 mm.The untreated powder was replaced with an equal weight of another sampleof the treated powder of Example 1 that was pressurized for 60 minutesat 120° C. Reconstituting the mix in the same manner produced a beverageat a height of about 60 mm that was completely covered by froth at aheight of about 16 mm. The froth produced by the treated and untreatedpowders had creamy texture and small bubble size, but only the mixcontaining the treated powder produced a cracking sound whenreconstituted. A continuous layer of froth at a height of only about 5mm was produced in the hot cocoa beverage without addition of treated oruntreated powder. All hot cocoa beverages had excellent flavor.

EXAMPLE 4

An additional 5 g sample of the untreated carbohydrate-free powder ofExample 1 was mixed with 13 g of Lipton® Cup-a-Soup®. The mix wasreconstituted with 180 ml of 90° C. water in a 250 ml beaker having 65mm internal diameter to produce a hot soup at a height of 60 mm that wascompletely covered by froth at a height of about 5 mm. The untreatedpowder was replaced with an equal weight of another sample of thetreated powder of Example 1 that was pressurized for 60 minutes at 120°C. Reconstituting the mix in the same manner produced a hot soup at aheight of about 60 mm that was completely covered by froth at a heightof about 15 mm. The froth produced by the treated and untreated powdershad creamy texture and small bubble size, but only the mix containingthe treated powder produced a cracking sound when reconstituted. Nosignificant amount of froth was produced in the hot soup withoutaddition of treated or untreated powder. All hot soups had excellentflavor.

EXAMPLE 5

An additional 10 g sample of the untreated carbohydrate-free powder ofExample 1 was mixed with 17 g of sugar-sweetened cherry-flavoredKool-Aid® brand soft drink mix and reconstituted with 240 ml cold waterin a 400 ml beaker having 72 mm internal diameter to produce a cold redbeverage at a height of 65 mm that was completely covered by white frothat a height of about 5 mm. The untreated powder was replaced with anequal weight of another sample of the treated powder of Example 1 thatwas pressurized for 60 minutes at 120° C. Reconstituting this mix in thesame manner produced a beverage at a height of about 65 mm that wascompletely covered by white froth at a height of about 13 mm. The frothproduced by the treated and untreated powders had creamy texture andsmall bubble size, but only the mix containing the treated powderproduced a cracking sound when reconstituted. No froth was produced inthe beverage without addition of treated or untreated powder. Allflavored beverages had excellent flavor.

EXAMPLE 6

An additional 5 g sample of the treated carbohydrate-free powder ofExample 1 that was pressurized for 60 minutes at 120° C. was mixed with15 g skim milk powder and 10 g sugar. The mix was reconstituted with 20ml of 5° C. water in a 150 ml beaker having 54 mm internal diameter andstirred with a spoon to dissolve. A cold fat-free dessert topping havinga thick, creamy, whipped-like, aerated texture was produced at a heightof about 35 mm. The treated powder was replaced with an equal weight ofanther sample of the untreated powder of Example 1. Reconstituting thismix in the same manner produced a topping with only slightly aeratedtexture at a height of about 25 mm. Reconstituting only the mixture ofskim milk powder and sugar in the same manner produced an unappealingrunny topping without aerated texture at a height of about 20 mm. Insummary, the untreated powder imparted about 25% volume overrun to thetopping preparation and improved the texture somewhat while the treatedpowder imparted about 75% volume overrun to the topping preparation andgreatly improved the texture. All toppings had excellent flavor.

EXAMPLE 7

An additional 10 g sample of the untreated carbohydrate-free powder ofExample 1 was mixed with 10 g of sugar and 2 g of soluble coffee powder.The mix was reconstituted with 240 ml of cold skim milk in a 400 mlbeaker having 72 mm internal diameter to produce a cold cappuccinobeverage at a height of about 65 mm that was completely covered by frothat a height of about 8 mm. The untreated powder was replaced with anequal weight of another sample of the treated powder of Example 1 thatwas pressurized for 60 minutes at 120° C. Reconstituting the mix in thesame manner produced a beverage at a height of about 60 mm that wascompletely covered by froth at a height of about 24 mm. The frothproduced by the treated and untreated powders had creamy texture andsmall bubble size typical of a cappuccino drink, but only the mixcontaining the treated powder produced a cracking sound whenreconstituted. A continuous covering of froth was not produced in thecold cappuccino beverage without addition of treated or untreatedpowder. All cappuccino beverages had excellent flavor.

EXAMPLE 8

An additional 10 g sample of the untreated carbohydrate-free powder ofExample 1 was mixed with the cheese powder provided in a package ofKraft® brand Easy Mac® macaroni and cheese dinner. Water was added tothe pasta in a bowl and cooked in a microwave according to packageinstructions. Addition of the cheese powder mix containing the untreatedpowder to the pasta produced a cheese sauce having frothy texture. Theuntreated powder was replaced with an equal weight of another sample ofthe treated powder of Example 1 that was pressurized for 60 minutes at120° C. Addition of this mix to the cooked pasta in the same mannerproduced a cheese sauce having very frothy texture. Only the cheesepowder mix containing the treated powder produced a cracking sound whenreconstituted. No significant extent of frothy texture was produced inthe cheese sauce without addition of treated or untreated powder. Allcheese sauces had excellent flavor.

EXAMPLE 9

An additional 10 g sample of the treated carbohydrate-free powder ofExample 1 that was pressurized for 60 minutes at 120° C. was mixed with28 g Quaker instant oatmeal. The mix was reconstituted with 120 ml 90°C. water in a 400 ml beaker having 72 mm internal diameter and stirredwith a spoon to dissolve the powder. A hot cereal was produced at aheight of about 40 mm that was completely covered by thick creamy frothat a height of about 13 mm. The froth was easily stirred into the cerealto create a rich, creamy, aerated texture. The froth was easily stirredinto the cereal to create a slightly aerated texture. The treated powderwas replaced with an equal weight of another sample of the untreatedpowder of Example 1. Reconstituting this mix in the same manner produceda hot cereal at a height of about 40 mm that was completely covered byfroth at a height of about 3 mm. Reconstituting only the instant oatmealin the same manner produced a hot cereal at a height of about 40 mm withno froth and without aerated texture. Only the oatmeal mix containingthe treated powder produced a cracking sound when reconstituted. All hotinstant cereals had excellent flavor.

COMPARISON EXAMPLE

A 50% aqueous solution of lactose and 33 DE glucose syrup solids (52%dry basis) skim milk powder (47% dry basis), and disodium phosphate (1%dry basis) was nitrogen injected and spray dried to produce a powdercontaining carbohydrate and protein. The powder had light yellow color,clean milky odor and flavor, a bulk density of 0.34 g/cc, a tap densityof 0.40 g/cc, a skeletal density of 0.71 g/cc, an internal void volumeof 52%, a true density of 1.49 g/cc, a T_(g) of 61° C., and moisturecontent of about 3%. Use of the powder in an instant sweetened coffeemix according to the method of Example 2 produced an amount of froththat completely covered the surface of the beverage to a height of about10 mm when about 11 g of the mix was reconstituted in a 250 ml beakerhaving 65 mm internal diameter using 130 ml of 88° C. water. Thesweetened coffee mix containing the powder had a clean milky flavor.

6 g of the powder containing carbohydrate and protein was pressurized at25° C. with nitrogen gas at 1000 psi for 5 minutes in a pressure vesseland then depressurized. Replacing the untreated powder with an equalweight of treated powder in the sweetened coffee mix revealed thattreatment increased the foaming capacity of the powder by about 160%.Knowledge of the reconstituted beverage mix froth density andincremental froth volume contributed by the treated and untreatedpowders was used to estimate the amount (corrected to room temperatureand pressure) of gas released by each powder. It was estimated that theuntreated powder released about 3.5 cc gas per gram of powder while thetreated powder released about 8.5 cc gas per gram of powder. The powderproduced a faint popping sound for a short time after depressurization,presumably due to bursting of walls surrounding diffusion-restrictedopen voids that were too weak to contain the pressurized gas. Bulkdensity of the treated powder was not altered, but skeletal densityincreased to 0.75 g/cc and internal void volume decreased to 50%,indicating the force of pressurization and/or depressurization opened aportion of previously vacuous internal voids, formed during particledehydration, to the atmosphere to increase foaming capacity. Thishypothesis is supported by the fact that even after one week, thetreated powder retained increased foaming capacity.

Another 6 g sample of the powder containing carbohydrate and protein waspressurized with nitrogen gas at 1000 psi in a pressure vessel, heatedin a 120° C. oven for 15 minutes, and then cooled to about roomtemperature before depressurizing. The treatment trapped pressurized gasin the powder and many particles exploded with a cracking sound for ashort time after depressurization. The treated powder had light yellowcolor, a cooked, astringent, processed flavor, a tap density of 0.45g/cc, a skeletal density of 0.98 g/cc, and an internal void volume of37%. Replacing the untreated powder with an equal weight of treatedpowder in the sweetened coffee mix revealed that treatment increased thefoaming capacity of the powder by nearly 6-fold, increasing the amountof gas released from about 3.5 cc gas per gram of powder to about 20 ccgas per gram of powder. The sweetened coffee mix containing the treatedpowder had an undesirable cooked, astringent, processed flavor.

Another 6 g sample of the powder containing carbohydrate and protein waspressurized with nitrogen gas at 1000 psi in a pressure vessel, heatedin a 120° C. oven for 30 minutes, and then cooled to about roomtemperature before depressurizing. The treatment trapped pressurized gasin the powder and a comparably larger proportion particles exploded fora short time after depressurization. The treated powder had darkeryellow color, caramelized odor, a harsh, astringent, processed flavor, atap density of 0.44 g/cc, a skeletal density of 0.94 g/cc, and aninternal void volume of 34%. Replacing the untreated powder with anequal weight of treated powder in the sweetened coffee mix revealed thattreatment increased the foaming capacity of the powder by 5-fold,increasing the amount of gas released from about 3.5 cc gas per gram ofpowder to about 17.5 cc gas per gram of powder. The sweetened coffee mixcontaining the treated powder had an undesirable harsh, astringent,processed flavor.

Another 6 g sample of the powder containing carbohydrate and protein waspressurized with nitrogen gas at 1000 psi in a pressure vessel, heatedin a 120° C. oven for 60 minutes, and then cooled to about roomtemperature before depressurizing. The treatment trapped pressurized gasin the powder and a comparably even larger proportion particles explodedwith a cracking sound for a short time after depressurization. Thetreated powder had brown color, caramelized odor, a harsh, astringent,burnt flavor, a tap density of 0.49 g/cc, a skeletal density of 0.98g/cc, and an internal void volume of 37%. Replacing the untreated powderwith an equal weight of treated powder in the sweetened coffee mixrevealed that treatment increased the foaming capacity of the powder bynearly 4-fold, increasing the amount of gas released from about 3.5 ccgas per gram of powder to about 13.5 cc gas per gram of powder. Thesweetened coffee mix containing the treated powder had an undesirableharsh, astringent, burnt flavor.

Although the invention has been described in considerable detail withrespect to preferred embodiments, it will be apparent that the inventionis capable of numerous modifications and variations, apparent to thoseskilled in the art, without departing from the spirit and scope of theinvention.

1. A foaming composition comprising: a powdered carbohydrate-freesoluble composition comprising protein particles having a plurality ofinternal voids containing entrapped pressurized gas.
 2. The foamingcomposition of claim 1, wherein the powdered carbohydrate-free solublecomposition comprises greater than 94% protein on a dry-weight basis. 3.The foaming composition of claim 2, wherein the powderedcarbohydrate-free soluble composition comprises essentially 100% proteinon a dry-weight basis.
 4. The foaming composition of claim 1, whereinthe soluble composition releases at least 2 cc of gas per gram of saidcomposition when dissolved in liquid at ambient conditions.
 5. Thefoaming composition of claim 1, wherein the soluble composition releasesat least 5 cc of gas per gram of said composition when dissolved inliquid at ambient conditions.
 6. The foaming composition of claim 1,wherein the soluble composition is selected from the group consisting ofa milk protein, soy protein, egg protein, gelatin, collagen, wheatprotein, and mixture thereof.
 7. The foaming composition of claim 6,wherein said protein is a hydrolyzed protein.
 8. The foaming compositionof claim 7, wherein said hydrolyzed protein is selected from the groupconsisting of a hydrolyzed gelatin, hydrolyzed collagen, hydrolyzedcasein, hydrolyzed whey protein, hydrolyzed milk protein, hydrolyzed soyprotein, hydrolyzed egg protein, hydrolyzed wheat protein, amino acid,or mixture thereof.
 9. The foaming composition of claim 7, wherein saidhydrolyzed protein comprises hydrolyzed gelatin.
 10. The foamingcomposition of claim 1, wherein said protein comprises gelatin.
 11. Thefoaming composition of claim 1, wherein said composition furthercomprises a buffering agent.
 12. The foaming composition of claim 11,wherein said buffering agent is a salt of an organic or inorganic acid.13. The foaming composition of claim 12, wherein said salt is selectedfrom the group consisting of a sodium salt, potassium salt, magnesiumsalt, calcium salt, citrate salt, fumarate salt, malate salt, phosphatesalt, or mixture thereof.
 14. The foaming composition of claim 1,wherein said soluble composition further comprises a dispersed fat. 15.A foaming composition, comprising: carbohydrate-free soluble foamingparticles comprising a protein and having a plurality of internal voidscontaining entrapped pressurized gas, said particles formed fromsubjecting said particles to an external gas pressure exceedingatmospheric pressure prior to or while heating said particles to atemperature of at least the glass transition temperature and thencooling said particles to a temperature below said glass transitiontemperature prior to or while releasing said external gas pressure in amanner effective to trap said pressurized gas within said internalvoids.
 16. The foaming composition of claim 15, wherein the powderedcarbohydrate-free soluble composition comprises greater than 94% proteinon a dry-weight basis.
 17. The foaming composition of claim 16, whereinthe powdered carbohydrate-free soluble composition comprises essentially100% protein on a dry-weight basis.
 18. The foaming composition of claim15, wherein said soluble composition releases at least 2 cc of gas pergram of said composition when dissolved in liquid at ambient conditions.19. The foaming composition of claim 18, wherein the soluble compositionreleases at least 5 cc of gas per gram of said composition whendissolved in liquid at ambient conditions.
 20. A soluble consumable foodproduct comprising a carbohydrate-free soluble foaming compositioncomprising protein particles having a plurality of internal voidscontaining entrapped pressurized gas.
 21. The soluble consumable foodproduct of claim 20, wherein said gas is present in an amount sufficientto produce at least about 5 cc of foam per gram of said composition whendissolved in liquid at ambient conditions.
 22. The soluble consumablefood product of claim 20, wherein said food product comprises a beveragemix selected from the group consisting of an instant coffee mix, instantcocoa mix and an instant tea mix.
 23. The soluble consumable foodproduct of claim 20, wherein the carbohydrate-free soluble compositioncomprises greater than 94% protein on a dry-weight basis.
 24. Thesoluble consumable food product of claim 23, wherein thecarbohydrate-free soluble composition comprises essentially 100% proteinon a dry-weight basis.
 25. The soluble consumable food product of claim23, wherein said food product comprises a beverage mix selected from thegroup consisting of an instant coffee mix, instant cocoa mix and aninstant tea mix.
 26. The soluble consumable food product of claim 24,wherein said food product comprises a beverage mix selected from thegroup consisting of an instant coffee mix, instant cocoa mix and aninstant tea mix.
 27. The soluble consumable food product according toclaim 22 wherein said instant coffee mix is an instant cappuccino mix.28. The soluble consumable food product 20 wherein said solubleconsumable food product comprises an instant food selected from thegroup consisting of a dessert product, instant cheese product, instantcereal product, instant soup product, and an instant topping product.29. A method for manufacturing a foaming composition, said methodcomprising: heating carbohydrate-free soluble foaming particlescomprising protein and having internal voids; applying external pressureexceeding atmospheric pressure to the carbohydrate-free soluble foamingparticles; cooling the carbohydrate-free soluble foaming particles; andreleasing the external gas pressure thereby resulting in pressurized gasremaining in the internal voids.
 30. The method of claim 29, whereinsaid applying external pressure is conducted prior to heating theparticles.
 31. The method of claim 29, wherein said applying externalpressure is conducted while applying heat to the particles.
 32. Themethod of claim 29, wherein said heating carbohydrate-free solublefoaming particles is conducted at a temperature of at least the glasstransition temperature of the particles.
 33. The method of claim 32,wherein said cooling is conducted prior to said releasing the externalpressure.
 34. The method of claim 32, wherein said cooling is conductedprior to said releasing the external pressure.
 35. The method of claim32, wherein said cooling is conducted while releasing the external gaspressure.
 36. The method of claim 29, wherein said carbohydrate-freesoluble foaming particles comprise greater than 94% protein on adry-weight basis.
 37. The method of claim 36, wherein saidcarbohydrate-free soluble foaming particles comprise essentially 100%protein on a dry-weight basis.
 38. The method of claim 29, furthercomprising spray drying an aqueous solution containing the protein toform the carbohydrate-free soluble foaming particles.
 39. The method ofclaim 38, wherein said spray drying comprises injecting gas into theaqueous solution.
 40. The method of claim 38, wherein said spray dryingis conducted without injecting gas into the aqueous solution.